**7. Future directions**

animal-derived products. Probiotics have been introduced into milk, formula, and other infant foods as a supplement, in order to improve the human gut microbiota stability and tap into the purported benefits of probiotics. The viability of probiotics is enhanced in its lyophilized state within low-fat milk or fruit juice by food formulators and manufacturers [22]. The improvement of the viability of probiotic strains can also be achieved by microcapsulation—a formulation approach that employs the use of microcapsules to package solids, liquids, or gases where these contents could be released in a controlled manner under specific conditions [22]. With this technique, the formulation, storage, and successful transport of probiotic strains to their destination in the gut is assured. Although probiotics are generally regarded as safe, there is a conscious effort to confirm that they do not carry and transfer genes conferring antimicrobial resistance, as this will defeat the purpose of probiotics usage [63]. By and large, the ultimate aim of the use of probiotics is to ensure the stability of the human and animal gut microbiota so as to take advantage of the symbiotic activity of the probiotic and the gut microbial community in the fight against multi-drug resistant gastrointestinal pathogens [8]. Probiotics are most commonly sold as foods or food supplements, powders, lozenges, tablets (could be chewable, enterocoated or not), sticks, capsules, bottle caps, sachets, stick packs, and oil suspensions (usually for babies) probiotic nasal spray and ointments have also been developed. Most probiotic products available in the market are dairy based foods, including fermented milks, yogurts, cheese etc. The health claims on most probiotics labels tend to be general and such products are intended for the general healthy population. However, manufacturers, food companies, and the media have dispersed unproven information about the purported health benefits of probiotics even before a comprehensive clinical trial has been conducted to validate the efficacy, and the risk–benefit association In terms of probiotics acceptability, although probiotics have been used in the food industries for decades, the discovery of novel strains and genetic manipulation of known strains (some of which are pathogenic) is usually accompanied with a mirror image of the consumer skepticism associ-

Another current application of beneficial gut microbes is the method of fecal microbiota transplantation (FMT). Fecal microbiota transplantation is a technique that involves the reconstitution of the deliberately-emptied gut of gastrointestinal-diseased patients with the gut microbiota of healthy donor as a therapeutic alternative measure to antibiotic administration for the restoration of the healthy gut microbiota [64]. This method has enabled the majority of those who have been suffering from antibiotic-associated diarrhea and inflammatory bowel diseases to lead a normal life after treatment. Although the filtered donor stool suspension can be passed into the gut of the recipient through rectal enema, nasoduodenal tube, or the nasogastric tube, colonoscopy is the most preferred method of stool suspension transfer. These donor stools could also be lyophilized and packaged into capsules, to be used in treating gastrointestinal infections. Stool banks are currently available in Europe and North America for the storage of tested, pathogen-free donor stools until they are needed by the medical practitioners [65]. Knowledge about the microbial composition of each donor stool and other components of the stool will also inform the medical practitioner and the patient on what to expect after transplantation. Due to the fact that the mental receptiveness of the fecal microbiota transplantation by the patient could have an effect on the effectiveness of this

ated with the marketing of genetically modified foods.

122 Antimicrobial Resistance - A Global Threat

As previously mentioned, MET is one proposed alternative to FMT. Apart from the fact that this procedure is less disgusting and less risky than FMT, it has the potential to be regulated and standardized more efficiently than FMT [67]. MET procedure involves the isolation, characterization, and screening of gut microbes (for antibiotic resistance, presence of virulence determinants, etc.) from a healthy donor. Gut microbes that pass the screening test will then be recombined into a microbial ecosystem where their combined efforts and synergistic relationships will be more effective in tackling invasive enteropathogens and opportunistic pathogens such as *Clostridium difficile* [68]. In the future, this consortium of synergistic gut microorganisms will be packaged and lyophilized in their live form into capsules and prescribed as a drug. MET is still in its infancy, and it also has to go through regulatory procedures just like a drug, and standardized before it is globally accepted for use in treating gastrointestinal diseases such as antibiotic-induced diarrhea as a therapeutic alternative measure to antibiotic administration. Nevertheless, it offers a promising and a more effective alternative to the use of FMT. Furthermore, since the exact composition of the consortium is defined, it will be easy to track the long-term effect of this potential drug on human health. Also, questions about the interaction between the consortium and the resident gut microbiota and their combined effect on the health of the human host will be answered in detail when this emerging procedure is studied in detail (which can be aided by adequate funding and government support) [67]. In the future, these studies will also open our eyes to the benefits MET has over FMT, and whether there are risks associated with the MET procedure. This information will give the medical community a holistic idea about the merits and demerits of the MET procedure, and will allow the medical practitioners (and patients) to make an informed decision on whether to use MET or stick to FMT or antibiotic administration (or a combination of either two of the three options, or combination of the three options). It will also be interesting to find out whether the MET procedure will be effective in the treatment of extra-intestinal diseases in the nearest future [67].

For the advancement of personalized medicine, another prospect is the use of antimicrobial peptides and/or nucleic acid-based methods to selectively kill pathogenic microorganisms in the gut without compromising the structure or function of the gut microbiota (a prominent demerit of antibiotics usage) [69]. Probiotic strains and the gut microbiota have also been thought of as reliable sources of new antimicrobial peptides and antimicrobials, such as bacteriocins [70]. This is because of the complex interaction between the microbial community and its host, especially in the production of metabolites that are active against a narrow spectrum and a broad spectrum of invasive pathogens. Nanotechnological and genetic engineering approaches could widen the precision and spectrum of activity of bacteriocins in future, making them the next generation of antimicrobials [71]. If these products can be utilized, they can effectively guard against antimicrobial resistance (in addition to the maintenance of gut microbial homeostasis) and can serve as therapeutic alternatives in the treatment of inflammatory bowel diseases, irritable bowel syndrome, colorectal cancer, and extra-intestinal diseases such as diabetes. Scientists believe that probiotics will replace antibiotics as drugs vetted by the FDA and European regulatory bodies in the nearest future. This laudable goal is dependent on the correct identification of probiotic strains (with the aid of next-generation sequencing technologies), the palatability of these strains to the sensory organ, validated storage and transport of intact cells to the gut (via microencapsulation approaches, or functional foods, and the fulfillment of all requirements and validation of all necessary stages for its approval as a new drug [72].

**Author details**

Ibadan, Nigeria

**References**

article\_818.pdf

ar-threats-2013-1

nlm.nih.gov/pubmed/20805405

Ayorinde O. Afolayan, Adewale Adetoye and Funmilola A. Ayeni\*

Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan,

Beneficial Microbes: Roles in the Era of Antimicrobial Resistance

http://dx.doi.org/10.5772/intechopen.79635

125

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\*Address all correspondence to: funmiyeni@yahoo.co.uk

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There is also a proposal that gut microbes can be genetically engineered so that they possess characteristics that detect what food is present in the gut, monitor inflammation, detect and fight against gastrointestinal pathogens thereby reducing reliance on antibiotics, and exert extra-intestinal effects such as the regulation of behavior and mood and treatment of cancer [73]. Genetically engineered microbes have been reported to be effective against *Vibrio cholerae* in mice especially when this pathogen was ingested 8 hours after the administration of the genetically engineered microbe [74]. There are still many ongoing trials seeking to manipulate and monitor the activities of genetically-engineered microbes in the gut, albeit in animal models. These microbes have to be tested for their safety and their ability to be fit enough to endure gastrointestinal conditions (stomach acid and bile) and successfully colonize the host's gut [75]. There is also the fear about the effect of horizontal recombinant gene transfer on the natural gut commensals. Although microbiome engineering is challenging, it is expected that this strategy will be less expensive and more effective than the traditional methods of gastrointestinal and other extra-intestinal disease control if achieved [76]. The major goal of genetic manipulation of gut microbes is to improve the health of humans.
